This invention is generally directed to agricultural implement tow bars of the type which enable a plurality of implements to be pulled by a single tractor and, more particularly, to a tow bar assembly having adjustable outrigger beams from at least one has a dolly connected thereto to which an implement, such as a hay baler, may be selectively hitched in such a manner as to enable the implement to track the natural contour of the ground over which the implement passes. The tow bar assembly is further of the type which allows the lateral spacing between the implements to be altered during movement through a field to adjust for spacing of windows, and to facilitate over-the-road transport and vehicle turning.
After hay and other vegetable matter has been cut and/or processed in the field, it is normally raked into windrows for purposes of facilitating baling of the material into either round or rectangular bales. Conventionally, a single hay baler is pulled through a field by a tractor or similar vehicle with the hay baler passing over a single windrow at a time. This requires repeated passes of the tractor through the field, thereby consuming not only fuel but also requiring multiple hours of vehicle operation and operator worktime.
In some agricultural environments, it has been proposed to utilize multiple implements pulled by a single tow bar to increase the rate of harvesting. By way of example, in U.S. Pat. No. 5,099,635 to Butkovich et al., a system for harvesting cotton is disclosed in which a tow bar assembly is provided for simultaneously carrying a plurality of cotton harvesting units. In U.S. Pat. No. 3,437,152 to Barrentine, an agricultural implement for pulling stalks, such as corn stalks from which corn has been harvested, is disclosed for pulling and grinding the stalks of multiple rows of the stalks simultaneously.
Another example of agricultural implement incorporating multiple cutting units is disclosed in U.S. Pat. No. 4,304,086 to Stuchl wherein a lawnmowing attachment has a plurality of lawnmowing decks which are mounted in laterally spaced relationship with respect to one another in order to maximize the cutting width as the implement passes over an area being mowed.
There is an ever-increasing need to reduce costs associated with the baling of hay and other forage products. By enabling a plurality of farm implements, such as baling machines, to be operated simultaneously, not only is it possible to reduce man hours associated with the baling but the operating hours of the harvesting machinery would be considerably reduced, especially with respect to the powering units, such as tractors, which will effectively extend the overall life of such vehicles.
It should be noted at this point in this application that the term "hay baler" is utilized. It should be noted that "balers" are also conventionally used for baling other forage materials such as peanut vines and the like which are acceptable as fodder. The term "hay baler" is meant to be generic to all types of balers having the features which are described herein with respect to the Description of the Preferred Embodiment and are not limited to hay balers per se.
In applicant's co-pending U.S. application referenced above, a tow bar assembly for multiple hay balers is disclosed which enables up to three separate hay balers to be pulled by a single tow bar having a pair of pivotable outrigger beams associated therewith. The tow bar assembly further includes a hydraulic system which allows a plurality of pumps to be mounted thereon which are used to drivingly engage the drive inputs to each of the balers which are hitched to the tow bar assembly. In this manner, up to three hay balers may be powered and pulled by a single tractor in such a manner that the lateral spacing between the balers may be varied as they are pulled through a field or as required to facilitate turning at the end of rows and for further facilitating transport of the balers on conventional roadways. The tow bar assembly is particularly adapted for use with smaller hay balers of the type which require a drive input from a power source and are therefore normally smaller and lighter in weight than many self-powered hay balers which are currently in use in many areas. Conventional self-powered round hay balers weigh in excess of a ton and, when the additional weight of hay being rolled within the balers is added to the gross weight of the implement as it is pulled through the field, the load imparted to an implement hitch tongue becomes significant and generally prohibits the use of outrigger beams which are designed to permit only horizontal or lateral movement of an implement during use.
In view of the foregoing, there remains a need to provide a tow bar assembly for use with a plurality of implements, such as a plurality of self-powered hay balers, which enables the larger and heavier self-powered implements to be effectively pulled through a field utilizing a single tow bar assembly.